Adherence of bacteria to soft or hard tissues is a prerequisite for many diseases of microbial origin. Oral streptococci have evolved means of colonizing certain areas of the human tooth and the colonization could lead to dental caries. Adherence of streptococci is a specific process which appears to result from multiple and cooperative interactions and is stabilized by hydrophobic forces. Using recently-developed and simple techniques, we have been able to isolate molecules (adhesins) which may be involved in the adherence process. We have observed that lipoteichoic acids can bind to salivary proteins and dextrans in alcohol solutions. An affinity column of Sephacryl (a cross-linked dextran) pre-equilibrated with alcohol will be used to purify the adhesins using alcohol to wash the column and water to elute the adhesins. Lipoteichoic acid-free adhesins can be similarly purified using a cell wall teichoic-Sephacryl conjugate. The adhesins will be used to coat hydroxylapatite (HA) beads to create artificial cell receptor sites and will also be used to inhibit adherence to the beads. Adhesins from both streptococci and saliva will be isolated and characterized. Graphical analyses (Scatchard, Hill, Langmuir, Klotz plots and others) will be used to evaluate the equilibrium and kinetic parameters of adherence of Streptococcus sanguis and S. mutans strains to artificial pellicles and saliva-coated HA. In addition, a promising new hydrophobic solvent, sulfolane, capable of solubilizing hydrophobic proteins without modifying their secondary structures, will be evaluated as an adherence inhibitor in order to provide more details about the role of hydrophobicity in adherence. This research should yield valuable new information on the adherence mechanisms of oral streptococci. This knowledge can then be applied to the rational design of new inhibitors of adherence, resulting in the possible prevention of many oral diseases.